Welding 101: Getting Started With MIG Welding Basics

Welding is an essential skill for hardcore and even moderate enthusiasts. Nuts and bolts can only take you so far. Eventually, if you’re serious about customizing and fabrication, you’re going to have to learn to weld. This useful skill will open up new fabrication options for your projects that may have seemed impossible before.

While taking a class or going to a seminar is a good idea, the truth is – with practice, patience, and the proper equipment, you can learn to MIG weld in your garage, on your own. We got together with our friends at Lincoln Electric to find out what you should know to get started in the world of MIG welding.

What Is MIG Welding?

For the purposes of this article we’ll be takings a look at the basics of MIG welding. Although you might know a little bit about the general ideas of welding, or might be familiar with some of the terms, we’ll start from the beginning and get everyone up to speed.

MIG Welding widens your options in terms of repairs and fabrication that you can do on your own.

MIG (Metal Inert Gas) is more properly referred to as GMAW (Gas Metal Arc Welding), but to keep things simple we’ll stick with MIG welding for this article. MIG is the most commonly used welding process in the world for many reasons: it’s fast, inexpensive, and welders can be easily trained to produce quality work.

With the proper setup and knowledge, even a small MIG welder can handle most repair and basic fabrication needs. This machine will become a go-to tool for everything from fixing your kid’s bicycle, to welding in new floor pans, and repair panels on your project car.

Gas or Flux

Using the Right Gas and Wire

We’ve talked about selecting the correct shielding gas before. It does bare repeating however, if you want to get the best results. Also selecting the wire that matches the material you’re welding is important:

For carbon steel you want to use a mix of 75% Argon, 25% CO2 this is also known as 75/25 in the industry. For this application you’ll also use steel wire.

For best results on stainless you’ll want to use what’s known as Tri-Mix gas. This is a mixture of Argon, CO2 and Helium. You’ll also need to run stainless wire in your machine.

In dealing with aluminum, it is recommended that you run 100% Argon gas. You’ll also run aluminum wire. In this case a spool gun is a good option as it puts the wire right behind the gun and reduces the risk of the fine aluminum wire getting damaged or stuck when feeding from the machine.

This is another area of extreme versatility with MIG welding. In order to get a quality weld, your work must be shielded. The welding process itself does several things. It creates extreme amounts of heat which breakdown chemicals within the air into smaller molecules, these substances can then contaminate the weld.

The process also generates a small electromagnetic field, which can also draw contaminants to the weld. Weld contamination may or may not be visible to the naked eye after a weld is finished. As such, the weld could fail or show signs of failure at a later time. You have two options to help control contamination, use gas or use a flux core wire.

Many of the MIG welders that Lincoln Electric sells will allow you to run either type of shielding. Using gas is a little more costly on the initial investment, it requires that you first source a gas supply or welding supply house to provide you with the proper mix of gas, which is typically a mix of Argon and CO2 for MIG welding carbon steel, aka mild steel.

Flux core welding wire contains a shielding substance within it to protect the weld. The advantage here is better portability as there is no heavy gas tank to haul around with your welder. The disadvantage is the mess, as flux core welding tends to leave more spatter. If you’re working on a farm implement out in the field you may not care about that. However, on an area of a project that will be visible to onlookers or car show judges that spatter will have to be cleaned up.

Safety First

Safety should always be your number one priority in your shop whether you’re a professional builder or just the average enthusiast wrenching in his garage. Trips to the ER are no fun, and trips to the funeral home are even worse. So don’t skimp on yours or your family and friends safety in the name of saving a few bucks.

Can your garage/shop handle the output?

It's difficult to enjoy the fruits of your labor if you can't see them. Protect your eyes and face with a quality welding helmet.

Even small 110 welders draw a lot of amperage/current. With this in mind, you need to be certain that your outlets and your wiring are up to the task. Don’t rely on a circuit breaker to be your saving grace either. We’ve seen home and shop garages that caught fire because the wiring got hot before the breaker tripped, setting fire to insulation and wood framing. This can be more than a bad day, fire is possibly the worst thing that could happen to a car guy and his family.

You can get the equipment to test your 110 system at most hardware stores. If you’re still unsure or you’re planning on using an even higher output welding system, spend the money to have a professional electrician check things out to let you know if it’s time for an upgrade. A dedicated outlet for your welder might not be the cheapest thing to have installed but it will be cheaper than replacing the burnt up wiring, damaged fuse panel, or the whole garage.

What to Wear

This is another area where we see guys skimp all the time. We know welding helmets aren’t cheap, and neither are welding jackets. You see guys all the time on cable TV shows close their eyes and strike a weld. This is really the wrong idea, the light from a MIG welder is brighter than the sun. Not only can this damage your eyes permanently, it can also lead to migraine headaches, and other serious problems.

Lincoln sells all the safety equipment you need bundled into different packages.

Then there’s the spatter. Last time we checked no one likes getting burned or scarred. Protect your eyes, face, hands and the rest of your body with a good helmet, a quality pair of gloves, a welding shirt, jacket or apron, leather shoes or boots, and thick pants or welding chaps.

Avoid Fumes

Welding fumes can present serious health risks. We’re not just talking about making you dizzy, light headed, or nauseous. There are permanent physical and neurological side effects that can result from prolonged exposure to the gasses and fumes generated by welding. You need to work in a well ventilated environment. There should be adequate airflow to provide you with fresh air, however the airflow should not be such that it pulls or pushes away all of your shielding gas. You could employ a high-vacuum, low-volume ventilation system. Lincoln and other companies offer these for production welding outfits, and companies. We would simply suggest that your work area be open, have a small amount of moving air. If you notice an accumulation of fumes take a break and clear the area out for a time by opening more doors or windows and/or switching on fans.

Equipment

If you don’t have a 230 outlet in your garage the 140c is great for what most guys will do at home. Having 230 though will open up your options. -Tom Myers

Whether you are a first time novice or a seasoned professional welder, Lincoln has a machine to cover your welding needs. We’ve presented a great article on this topic to help you choose the right machine for your use. For this article we’d like to mention the Lincoln POWERMIG 140c and POWERMIG 180 series welders. Tom Myers, application engineer for Lincoln Electric, talked with us for this story to delve deeper into the dos and don’ts of MIG welding.

Myers told us “If you don’t have a 230 outlet in your garage the 140c is great for what most guys will do at home. Having 230 though will open up your options.” Either of these would be good choices for a beginner, both offer easy operation and controls, and both can be used with flux core wire or with gas. It’s important to mention as well that as with all tools and equipment, you get what you pay for. There is cheaper equipment on the market, but there are also cheaper cars, cheaper car parts, and cheaper hand tools. Quality equipment can save you time, headaches, and money in the long run.

Machines like the POWERMIG 140c and POWERMIG 180 are not only great entry level equipment, they're also workhorses that will handle most fabrication needs for those of us working out of our home garages.

Other items you may want to consider purchasing aside form what we’ve already talked about:

Grinder for beveling edges or cleaning up the really nasty stuff.

Set of wire brushes for cleaning your work prior to beginning.

Good set of welding pliers.

Welding cart to place your welder on. You could also build this cart if you’re so inclined and resourceful, it might make a good first project to learn on.

Cover or cabinet to store your welder and welding dedicated tools.

Welding stand or table for working on projects that aren’t already attached to a car or something else large. Again, you could build this as a project yourself.

Prep Work

Talking with Tom Myers from Lincoln, we learned that MIG Welding is just like many other automotive projects – quality prep work is essential to achieving the desired outcome in welding. There’s a joke that painting a car is 80% prep work and 20% actual painting. This holds true for welding as well. To achieve effective, and lasting welds, you must prep the materials to be welded properly.

This frame has been repaired with a MIG welder. Notice how clean the metal is in the area where the repairs were performed.

This involves making sure that the surfaces to be welded are clean, free of paint, rust, grease, dirt, or other materials. Cleaning and prep work are where things like a grinder, a wire brush, and compressed air will come in handy. You want to be working with clean, bare metal. Another note here is do not use chemical solvents to prep and clean, unless you are certain that they will not break down into harmful gasses.

Many solvents like brake cleaners, etc. are used widely for cleaning surfaces in auto repair. However some of these cleaners contain chemicals that will be left behind in small traces. Those small trace chemicals can then be broken down further by the welding process, potentially becoming extremely harmful gasses.

We should also mention that not only does the area that you will be welding need to be clean, but also the area where the welding lead will be clamped. You should also make sure that whatever the welding lead (often incorrectly called the ground) is clamped to has sufficient capacity to withstand the electrical current load. This is where working on a welding table can come in handy. A steel welding table can help provide the necessary surface area for the welding lead if you are working with small parts.

Welding

Welding is like any other skill, you probably couldn’t rebuild a carburetor, set the timing on an engine, or even do a simple brake job the first time you wrenched on your own car. It takes time, patience and practice to master.

The worst thing you can do is allow yourself to become angry or frustrated. With patience, it won’t be long before you’ll be taking on those new project ideas, and you’re buddies will probably be begging you to help them out as well.

Machine Setup

The chart on the inside of the POEWRMIG 140c and 180 will guide you to the proper settings for the material you're welding.

Practice makes a good welder. While learning, take note of what you did right and what looks wrong.

Repeat the motion of drawing a lower case letter “e” or “u” as you weld to control your speed and keep the puddle flowing.

Get a book. Keep a reference book in the garage with your welding gear (or print out this guide).

Keep the gun a constant distance from the puddle (about half an inch).

Spread your welds out to control heat and voltage on thin sheet metal like body panels.

Push the gun instead of pulling it, especially while you’re learning.

Use two hands, and stabilize your body, lean on something.

Watch your gas flow. If the gas level drops when you pull the trigger adjust the settings.

Don’t take on too much. Day one welding should be something simple, practice only.

One of the biggest fears of many who have never welded is that they won’t know how to setup their machine. There is plenty to consider, the type of wire to use, including the wire thickness, as well as the material that makes up the wire. A good rule of thumb here is rather simple. Thinner metals will require you to use thinner wire, thicker metals use thicker wire.

The same goes for the wire type (as we listed above), if you’re welding mild steel you will want to use a steel wire, stainless steel, a stainless wire, and aluminum use aluminum wire. This ensures your wire has a melting point as close to your working material as possible and most closely matches it from a metallurgical standpoint.

Amperage and wire speed are also areas of concern that must be properly set for each project. Fortunately, Lincoln has this covered with their welders. Inside the cover on the case of the welder you will find a helpful chart. Using the information in the chart you can properly set your wire speed and electrical output/amperage, based on the material you’re welding and the type of weld (MIG or Flux).

Process

With everything set properly it’s time to weld. Lincoln always recommends practicing on some scrap metal until you get the hang of the controls and technique. One idea we’ve seen is to buy some strips of 3/8-inch or 1/4-inch scrap metal to practice on. Start by just practicing beads on these strips before you ever even try to join two pieces of metal. Just make some passes across the shortest part of the strip.

Using the Best Practices and Top 10 Tips from Lincoln (to the left) – you can begin to become more comfortable with your welding technique and the use of the machine. Play with methods and settings on your welder to find a sweet spot. This is fundamental welding 101, and just like a lot of skills, the strength and quality of your welds will come down to how good you are at the fundamentals.

The Good, The Bad, The Ugly – What Makes A Good And A Bad Weld?

Beginners tend to travel too fast and hold the gun too far away. If you travel too fast you get a ropey looking bead.

In the video above Lincoln walks us through some very important trouble shooting techniques for creating a good weld. Bad welds can be the result of any number of causes. Large welding companies have quality controls in place to ensure they have good welds.

As hobbyists we don’t have the luxury of having our work inspected by an engineer, so use your judgement based off what you see and hear during and after. We’ve listed a few examples of good and bad welds below. We’ve also included the above video which covers many of these and other mistakes so that you can see and hear what happens with each one.

Good Weld

Here's an example of a good weld with an even pace and penetration.

Working with the pros at Lincoln we were able to gather some good dos and don’ts. Let’s start with a good MIG weld for illustration purposes. When everything is working right you’ll notice a minimal amount of spatter and sparks. You’ll also hear a rhythmic crackle that occurs at the proper temp. and settings. This sound is almost something that you have to hear in person to understand. A good weld has a clean appereance to it, indicating minimal or no contamination. Discoloration to the work material is minimized as well. It should be solid with no porosity or craters. Good welds tend to have that “stack of dimes” appearance to them as well.

The photo above shows two examples of issues with wire feed speed. The left bead is where the wire feed speed is set too fast. When this occurs you will hear a very fast arching or crackle noise. This is caused by too much wire coming out of the gun for the set voltage. The bead on the right is where the wire feed speed is set too slow. When this occurs during welding the arc has a low slow crackle sound to it. You’ll notice that there is a lot of heat discoloration in this weld, that’s due to the slow speed and high amperage causing discoloration, it can also cause distortion in the metal.

Weld travel speed is another area where beginners often have trouble. The photo above demonstrates too slow a travel speed on the left and too fast a travel speed on the right. When your travel speed is too slow you will typically hear almost no definition to the crackle, almost like a steady noise to the arc rather than the rhythmic pulse that you would normally hear. The bead will be fat (from too much of the puddle building and piling up), have a dull appearance and may also have some craters in it. You can also see with that bead that there is a large amount of heat being put into the work material from the discoloration and dulling of the metal.

The bead on the right of this photo is one where the travel speed is too fast. This is just the opposite of traveling slow. There’s also not much crackling going on with this weld because the travel speed is moving too fast, but the bead has a thin and almost ropey appearance to it. It also does not have adequate heat to cause proper fusion or penetration (rings of heat around the weld) between the welds.

Failure to maintain the proper 3/8-inch wire stick-out distance (distance the wire hangs out from the gun upon starting a weld) is also a common cause of bad welds for beginners. Above we see examples of too far or too close. When “stick-out” is too far the input voltage actually drops, this causes less penetration but also causes the heat to rise as is evident in the discoloration. The welding bead will also have a very convex shape, and be beaded up. When stick-out is too close you can not see your puddle or follow the weld joint very well. You’ll also run the risk of burning back into the welding torch or even putting dents or craters in the weld by bumping into the molten puddle with the torch.

Too Little Shielding Gas

Low or no shielding gas shows signs of contamination.

When you run into low or no shielding gas as the two photos above show you’ll notice several things. First during the weld process you’ll notice a lot of spatter and hear way more crackling than you’re used to. This is when the sparks will really start flying. You’ll also notice your welds are very pourous, they may have lots of pinholes or craters in them. There will also be contamination present. Typically when you see a bead like the one in the left picture there are two possible causes, the first is a lack of shielding gas, the second would be contaminated material.

The Final Word

We’ve only covered the basics of MIG welding so we can begin to master these techniques together. There are obviously entire books and curriculum dedicated to the subject but working with the pros over at Lincoln – these insider tips will get you up to speed quickly. You don’t need a college degree to get started, and you don’t have to be an engineer to figure out how to set up a machine. MIG welding is perhaps the easiest form of welding because it’s also the most versatile.

You don’t have to spend a fortune to get started, a small unit like the PowerMIG 140C will do a lot of work, especially automotive sheet metal. From patching a panel to chopping a top, this skill and the cost of the equipment will pay for themselves in both the dollars saved on paying someone else to do the work, and the satisfaction you’ll get by knowing you did the job yourself. With patience and some practice anyone can learn to MIG weld in their home garage and put this valuable skill to use on their own projects.